1. Field of the Invention
The present invention relates to a recording medium and a tape driving-apparatus accommodating thereto.
2. Description of the Related Art
A so-called tape streaming drive has been known as a driving apparatus which is capable of recording/reproducing digital data to/from a magnetic tape. Although it depends on the length of a tape of the tape cassette, i.e., a medium, the tape streaming drive is capable of having an enormous amount of recording capacity of several tens to several hundreds giga bytes for example. Therefore, it is widely used for backing up data recorded in a medium such as a hard disk of a computer main body for example. It is also considered to be suitable for use in storing image data whose data size is large.
Then, as the tape streaming drive as described above, there has been proposed one which is arranged so as to record/reproduce data by using a tape cassette of an 8 mm VTR as a recording medium and by adopting a helical scan scheme by means of a rotary head for example.
The tape streaming drive utilizing the 8 mm VTR tape cassette as described above uses SCSI (Small Computer System Interface) for example, as an input/output interface for recording/reproducing data.
Then, data supplied from a host computer for example is inputted via the SCSI interface during recording and the inputted data is compressed and encoded in the predetermined manner to be recorded in the magnetic tape of the tape cassette.
During the reproduction, data in the magnetic tape is read and decoded as necessary to be transmitted to the host computer via the SCSI interface.
By the way, a data storage system composed of the tape streaming drive and the tape cassette as described above requires various positional information on the magnetic tape and information regarding to the history of use of the magnetic tape as management information utilized by the tape streaming drive in managing the recording/reproducing operation and the like for example, to adequately implement the recording/reproducing operation on the magnetic tape of the tape cassette.
Then, it is conceivable to provide an area for such management information at the head of the magnetic tape.
Thus, the tape streaming drive accesses to the area of the management information described above to read the required management information before executing the data recording or reproducing operation to/from the magnetic tape, and based on this management information, executes various processing operations so that the recording/reproducing operation thereafter is adequately carried out.
After ending the data recording/reproducing operation, the tape streaming drive accesses to the area of the management information again to rewrite the contents of management information which has become necessary to be changed due to the recording/reproducing operation and is ready for the next recording/reproducing operation. After that, the tape streaming drive unloads or ejects the tape cassette.
However, when the tape streaming drive carries out the recording/reproducing operation based on the management information as described above, it must access to the area of the management information at the head of the magnetic tape in starting the operation in either cases of the recording and reproducing operation, and access to the area of this management information to write/read information also in ending the operation. That is, it is unable to load or unload the tape cassette on the way of the magnetic tape in ending to record/reproduce data.
In case of the tape streaming drive, it takes a considerable time to access to the head of the magnetic tape or to the area of the management information at the head of a partition because the magnetic tape has to be fed physically to make the access. The magnetic tape has to be fed more and it take more time particularly in ending to record/reproduce data at the position physically separated from the area of the management information on the magnetic tape.
Thus, there has been a problem that it takes time in ejecting or replacing the tape cassette in the case of the tape streaming drive.
In view of the problem described above, it is an object of the invention to enable to quickly eject or replace a recording medium and to improve the reliability of a system.
In order to achieve the above-mentioned object, an inventive recording medium comprises a magnetic tape and a memory for recording management information for managing a recording/reproducing operation to/from the magnetic tape.
The memory is also provided with areas for storing information on tape position in ejecting out of the tape driving apparatus. The tape positional information is information on reel diameters within the tape cassette in which the magnetic tape is wound around reels.
When a plurality of partitions may be set on the magnetic tape, the memory is provided with areas for storing information for discriminating a partition in ejecting out of the tape driving apparatus.
The inventive tape driving apparatus comprises tape driving means for running the magnetic tape of the loaded tape cassette and for recording/reproducing information to/from the magnetic tape which is being run; memory driving means for reading/writing management information from/to the memory of the loaded tape cassette; tape position detecting means for detecting the information on the position of the magnetic tape which is being run by the tape driving means; and control means for causing the memory driving means to store the tape positional information in ejecting the tape cassette in the memory within the tape cassette.
When the magnetic tape has a plurality of partitions, the control means causes the memory driving means to store information for discriminating a partition in ejecting the tape cassette to the memory within the tape cassette.
The the control means of the inventive tape driving apparatus also causes the memory driving means to read the tape positional information at the previous ejection when the tape cassette is loaded, causes tape position detecting means to detect the tape positional information, compares these tape positional information and enables to record/reproduce data to/from the magnetic tape when the result of comparison is adequate.
When a plurality of partitions are set on the magnetic tape, the control means causes the memory driving means to read information for discriminating a partition at the previous ejection from the memory when the tape cassette is loaded, causes the tape driving means to read partition discriminating information on the magnetic tape, compares these partition discriminating information and enables to record/reproduce data to/from the magnetic tape when the both results of comparison of the partition discriminating information and of the tape positional information are adequate.
When the result of comparison is not adequate, the control means causes the tape driving means to run the magnetic tape forcibly to the starting end position.
That is, the memory, e.g., an nonvolatile memory, is provided within a case of the tape cassette to cause it to store the management information. It then enables to eliminate the need for rewinding the magnetic tape to the tape top for example, in loading/unloading the tape. It also allows a large number of partitions to be set on the tape to allow the tape to be adequately managed.
Still more, it is possible to realize the adequate recording/reproducing operation after loading by discriminating, in loading the tape, whether or not the tape is loaded correctly at the previous unload position in correspondence to the operation in which the tape may be loaded/unloaded on the way.
To that end, the tape positional information and partition discriminating information are stored in the memory at each time in ejecting (unloading) the tape cassette. Then, when the recording medium is charged and the magnetic tape is loaded, the tape positional information detected at that time is compared with the tape positional information stored in the memory. In some cases, it is confirmed whether or not the recording medium is loaded correctly by comparing the partition discriminating information read from the magnetic tape with the partition discriminating information stored in the memory.
The specific nature of the invention, as well as other objects, uses and advantages thereof, will clearly appear from the following description and from the accompanying drawings in which like numerals refer to like parts.